The present invention relates generally to an apparatus and method for measuring the speed and/or acceleration of a vehicle. More particularly, the invention relates to the use of a projected radiation beam that is blocked by passing vehicles.
Various arrangements for measuring the speed and/or acceleration of a vehicle moving along a vehicle path such as a roadway have been known. One such device uses radiation sources on one side of the roadway, projecting a beam across the roadway to be received by a respective detector. The detectors are on the opposite side of the roadway from the radiation sources. The detectors detect when the beam is blocked by a wheel of the vehicle. A calculating circuit determines the speed and/or acceleration of the vehicle based on information from the detectors.
A disadvantage of this known arrangement is that the radiation sources and detectors must be placed on opposite sides of the roadway from each other. Since both the detectors and radiation sources require power to operate, this means that a separate power supply must be provided on each side of the roadway.
Another disadvantage of the known arrangement is that it is difficult to align the sources and detectors so that the beam hits the detector.
Still another disadvantage of the known arrangement is that there is no means for approximating the size and/or mass of the passing vehicle, information useful in the calculation of the Specific Power generated by the vehicle. Specific Power is crucial to correlating on-road in-use emissions from vehicles to stationary loaded-mode tests when the embodiment of this invention is applied to on-road in-use emissions testing.
No currently known embodiment of speed and acceleration can be implemented such that more than one group of sensors can connected in series (xe2x80x9cdaisy-chainedxe2x80x9d) to produce multiple sets of speed and acceleration measurements.
Yet another disadvantage of known arrangements is that there is no provision for a convenient support structure that can support more than one unit such as sender units, detector units, or reflector units, to provide a fixed spacing between the units while also permitting the support to be adjustable for uneven surfaces or for mounting on a curb when desired. Also, there is no provision for making such a support able to be disassembled for storage and/or transport.
Accordingly, it would be desirable to have an arrangement where power could be supplied on only one side of the roadway and which is easier to align than conventional arrangements.
It would also be desirable to have a convenient support structure that can support more than one unit such as sender units, detector units, or reflector units, to provide a fixed spacing between the units while also permitting the support to be adjustable for uneven surfaces or for mounting on a curb when desired. Also, it would be desirable to have a provision for making such a support able to be disassembled for storage and/or transport.
In accordance with one embodiment of the present invention, an apparatus is provided for determining the speed and/or acceleration of a vehicle traveling on a vehicle path. The apparatus has a first radiation source arranged at a first side of the vehicle path and a first reflector arranged on a second, opposite side of the vehicle path from the radiation source that reflects the radiation from the first radiation source back towards the first side of the vehicle path. A first detector is arranged at the first side of the vehicle path that receives the reflected radiation from the first reflector and detects a presence or absence of the reflected radiation. A second radiation source is arranged at the first side of the vehicle path and a second reflector is arranged on the on the second, opposite side of the vehicle path from the second radiation source that reflects the radiation from the second radiation source back towards the first side of the vehicle path. A second detector is arranged at the first side of the vehicle path that receives the reflected radiation from the second reflector and detects a presence or absence of he reflected radiation. A controller which is operatively connected to the first and second detectors calculates at least one of the speed and acceleration of the vehicle in response to the detection by the first and second detectors.
The invention provides a method for measuring at least one of the speed and acceleration of a vehicle traveling on a vehicle path by emitting radiation from a first side of the vehicle path, then reflecting the radiation emitted at a second, opposite side of the vehicle path back towards the first side of the vehicle path. The reflected radiation is received at the first side of the vehicle path and a presence or absence of the reflected radiation is detected. At least one of the speed and acceleration of the vehicle is calculated in response to the detecting step.
In another aspect, the invention provides a support for supporting two or more units used in a system for measuring a speed and or acceleration of a vehicle, with the support able to rest on a surface, has an elongated bar on which the units are mounted. A first leg and a second leg are both mounted to the bar. A third leg is mounted to a rear portion. The legs in some embodiments are height-adjustable.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract included below, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.